WASHINGTON -- The difference in life expectancy between black and white Americans widened in 1989, a trend that has been evident for half a decade, the government said on Tuesday.

The rising death rate of young black men -- primarily because of murder and AIDS -- is probably the reason blacks have a lower life expectancy than whites, officials said. But they said significant differences between the races in infant mortality and the mortality of older people also contribute.

``We are seeing a persistent and growing difference in health between the black population and the white population. Probably one of the more perplexing aspects of that growing differential is that it is striking all age groups,`` said Harry M. Rosenberg, chief of mortality statistics of the National Center for Health Statistics.

The report was the final tabulation of death rates for 1989, the last year for which complete statistics are available.

The most striking finding was the difference in death rates between blacks and whites in the 25-to-34 age bracket, where the effect of AIDS and murder is most evident.

For blacks, the rate was 280.6 deaths per 100,000 population in 1989. For whites, it was 118.3 per 100,000 the same year. For both races, the mortality rate in this age group declined until the middle 1980s, then began to rise again. However, for blacks, the increase has been much steeper.

LIFE EXPECTANCY

Results from the National Center for Health Statistics study:

-- BLACK MEN: Life expectancy dropped slightly, from 64.9 to 64.8 years. This downward trend was first seen between 1984 and 1985. Before that, the life expectancy of black men had risen each year for decades.

-- BLACK WOMEN: Life expectancy rose slightly, from 73.4 to 73.5 years.

-- WHITE MEN: Life expectancy rose from 72.3 to 72.7 years.

--WHITE WOMEN: Life expectancy rose from 78.9 years to 79.2 years.

-- SUICIDE: For the third consecutive year, the suicide rate declined slightly.